package com.gxc.tree;

/**
 * 给你一棵二叉树的根节点 root ，翻转这棵二叉树，并返回其根节点。
 */
public class InvertTree {

    public TreeNode invertTree(TreeNode root) {
        if (root == null) return null;

        TreeNode left = invertTree(root.left);
        TreeNode right = invertTree(root.right);
        root.left = right;
        root.right = left;
        return root;
    }
}

 class TreeNode {
      int val;
      TreeNode left;
      TreeNode right;
      TreeNode() {}
      TreeNode(int val) { this.val = val; }
      TreeNode(int val, TreeNode left, TreeNode right) {
          this.val = val;
          this.left = left;
          this.right = right;
      }
  }
